LAUSR

Learning Objectives: Pulmonary embolism (PE) is a rare but potentially fatal complication in neonates. Anticoagulation remains the mainstay of treatment; however, pediatric data remains sparse. Methods: A neonate with hypoplastic left heart syndrome underwent stage one operative palliation with a modified Norwood procedure with Sano shunt. Following planned delayed chest closure; transthoracic echocardiogram was significant for a thrombus on the common atrial line despite being started on heparin for shunt prophylaxis. On post-operative day 13, the common atrial line was removed and the patient extubated to nasal cannula. The following morning, the patient had acute respiratory failure that was managed initially with noninvasive ventilation. Transthoracic echocardiogram was obtained and showed good function, patent Sano shunt and stable thrombus along the right atrial wall. However, secondary to refractory hypoxemia, hypercarbia, and altered mental status the patient was intubated and started on mechanical ventilation. The history of a common atrium thrombus, significant dead space fraction of 0.6 and the acute nature of the respiratory failure were suspicious for acute PE. Therefore, MRA was obtained and confirmed the diagnosis of PE in the distal right pulmonary artery (PA) as well as indirect evidence of a thrombus in the distal left PA. A multidisciplinary team made the decision to use systemic thrombolytic therapy over catheter-directed thrombolysis given thrombi in multiple vessels. Prior to starting systemic thrombolytic therapy, a head MRI was obtained and was significant for acute infarction of the left corona radiata and bilateral subdural hematomas. Given the MRI findings, the patient was continued on standard anticoagulation therapy including aspirin. The patient was successfully extubated and later discharged home with complete recovery. Results: Our case is the first that describes acute PE in the immediate post-operative period following modified Norwood procedure with Sano shunt. It demonstrates the need to include PE in the differential diagnosis in the setting of rapid status changes after the Norwood procedure. Given the limited literature available regarding best practice, there is a need for future studies to provide a gold standard of treatment for pediatric patients with PE.